- What is the dart frog toxin allegedly used to kill Alexei Navalny? BBC
- Russia accused of killing Navalny with dart frog toxin. What we know about the rare poison Axios
- Rubio says US does not dispute Navalny poisoning assessment by Europeans Reuters
- Russian opposition figure Navalny killed by toxin found in poison dart frogs, Europeans say CNN
- Rubio says “no reason” to doubt Navalny was killed by dart frog poison MS NOW
